vendredi 6 janvier 2012

An engine firing on Jan. 11 will be the biggest maneuver that NASA's Mars Science Laboratory spacecraft will perform on its flight between Earth and Mars.

The action will use a choreographed sequence of firings of eight thruster engines during a period of about 175 minutes beginning at 3 p.m. PST (6 p.m. EST or 2300 Universal Time). It will redirect the spacecraft more precisely toward Mars to land at Gale Crater. The trajectory resulting from the mission's Nov. 26, 2011, launch intentionally misses Mars to prevent the upper stage of the launch vehicle from hitting the planet. That upper stage was not cleaned the way the spacecraft itself was to protect Mars from Earth's microbes.

This is an artist's concept of NASA's Mars Science Laboratory spacecraft during its cruise phase between launch and final approach to Mars. Image credit: NASA / JPL-Caltech.

The maneuver is designed to impart a velocity change of about 12.3 miles per hour (5.5 meters per second).

"We are well into cruise operations, with a well-behaved spacecraft safely on its way to Mars," said Mars Science Laboratory Cruise Mission Manager Arthur Amador, of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "After this trajectory correction maneuver, we expect to be very close to where we ultimately need to be for our entry point at the top of the Martian atmosphere."

The mission's schedule before arrival at Mars on Aug. 5 in PDT (Aug. 6 in Universal Time and EDT) includes opportunities for five more flight path correction maneuvers, as needed, for fine tuning.

The Jan. 11 maneuver has been planned to use the spacecraft's inertial measurement unit to measure the spacecraft's orientation and acceleration during the maneuver. A calibration maneuver using the gyroscope-containing inertial measurement unit was completed successfully on Dec. 21. The inertial measurement unit is used as an alternative to the spacecraft's onboard celestial navigation system due to an earlier computer reset.

Diagnostic work continues in response to the reset triggered by use of star-identifying software on the spacecraft on Nov. 29. In tests at JPL, that behavior has been reproduced a few times out of thousands of test runs on a duplicate of the spacecraft's computer, but no resets were triggered during similar testing on another duplicate. The spacecraft itself has redundant main computers. While the spacecraft is operating on the "A side" computer, engineers are beginning test runs of the star-identifying software on the redundant "B side" computer to check whether it is susceptible to the same reset behavior.

The Mars Science Laboratory mission will use its car-size rover, Curiosity, to investigate whether the selected region on Mars inside Gale Crater has offered environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.

On Jan. 15, the spacecraft operations team will begin a set of engineering checkouts. The testing will last about a week and include tests of several components of the system for landing the rover on Mars and for the rover's communication with Mars orbiters.

The spacecraft's cruise-stage solar array is producing 780 watts. The telecommunications rate is 2 kilobits per second for uplink and downlink. The spacecraft is spinning at 2.04 rotations per minute. The Radiation Assessment Detector, one of 10 science instruments on the rover, is collecting science data about the interplanetary radiation environment.

As of 9 a.m. PST (noon EST, or 1700 Universal Time) on Saturday, Jan. 7, the spacecraft will have traveled 72.9 million miles (117.3 million kilometers) of its 352-million-mile (567-million-kilometer) flight to Mars. It will be moving at about 9,500 mph (15,200 kilometers per hour) relative to Earth and at about 69,500 mph (111,800 kilometers per hour) relative to the sun.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory mission for the NASA Science Mission Directorate, Washington.

The EMU spacesuit crew of the Space Shuttle and ISS is gradually increased from 11 to 19 layers of protection to a thickness from about 5-8 mm. In its 2010 version, it consists of an assembly of 18 components produced by some 80 companies and assembled in the office headquarters in Houston, Texas. The size of the different elements varies between 8 mm and 76.2 cm for the water supply. ILC Dover tells us that a combination EMU requires about two and a half years of work about 5000 hours.

As we mentioned, many materials are components of the space suit. Many materials make use of synthetic polymers that can be found on the market and you may have.

The different layers of protection

The purpose of the space suit (or Space Suit Assembly SSA) is to protect the astronaut severe conditions prevailing in space: the absence of air, heat, cold, radiation and impacts of meteoroids and other debris. It includes two practical clothing: underwear body for comfort (LCVG) above which is the famous astronaut pressure suit comprising a succession of white insulating layers and protective layers (TMG).

The fabric inside the pressure suit is made of nylon thread as it is rot-proof, highly resistant, flexible, lightweight insulation. Perspiration that would result is evacuated through LCVG. The second layer is made of Spandex or Lycra (as LCVG).

Internal structure of a typical combination SSA carried by the crew of the space shuttle during the EVA. Its structure TMG has hardly changed for over 20 years. Document ILC Dover (http://www.ilcdover.com/Space-Suits/) adapted by the author.

Then the pressurized layer is nylon coated urethane (a foam-based ethane also known as carbamate). It is covered by a Dacron fabric that a type of polyester (it is used to manufacture such as canvas pants) that maintains structural layer pressurized.

Above is a non-slip nylon-covered neoprene which is a spongy material insulation (it is also the combination of scuba divers).

The five following layers but may be more likely provide protection called TMG. It is made of aluminized Mylar (which is also used to make sunscreens and insulating blankets) which assumes the role of thermal insulation and protection against cosmic rays. When it contains nylon it also protects against micro-meteoroids.

Finally, the outer layers are made of Ortho which is a blend of Gortex (it is also used to make boots), Kevlar (known to be bullet-proof) and Nomex to ensure good mechanical protection (against abrasion, wear, impact, tearing, etc.).

However, this combination offers no protection against high-energy particles (protons, electrons) released during solar flares (CME). In this case the astronauts need to take refuge in a shelter in the space shuttle and have the heat shield of the shuttle facing the sun.

The materials used to manufacture the combination are selected to prevent formation of mold or bacteria growth, for their strength and resistance. That is why we find synthetic fibers (polymers) and metal fibers. However after each flight, the combination is cleaned and dried.

The torso, gloves and boots

Under the protection of TMG, the upper part of the combination lies a hard shell called "Hard Upper Torso" (HUT) made of fiberglass. Its main purpose is to protect the vital parts of the body of the astronaut. He also comfort by supporting the PLSS backpack and various tools that attach to the torso (workstation, etc).

The HUT has four openings provided with fastening rings which attach the helmet, the lower torso (LTA) and the two arms (in fact the shoulders to the arms).

In addition, adapters were added to fix the connections of the PLSS and the display module and control DCM. The torso HUT has several receptacles receiving the bag of water, the communication system and vents and holes for the passage of cables and other supply lines.

All that hard is much more comfortable than previous models because the openings were expanded and placed closer to the body, outside the opening angle of the members, which has eliminated the flared rim, leaving more space to move my arms.

A general description of the combination ISS EMU without the SAFER.

Image above: The Hard Upper Torso (HUT). Note the tilt of the neck for easy close observation through the headphones. The base of the shell ends up in the abdomen.

The LTA

The lower part of the combination is called "Lower Torso Assembly" (LTA). It includes pants (size high, to the navel!), Boots and small parts protecting the lower abdomen and waist, knees and ankles. It is made of nylon protected by a layer Rethans and TMG.

In combination with low pressure, the joints are generally covered by a bellows which ensures free movement of the astronaut to the point that without the PLSS it would be a movement without experiencing hardship.

The gloves contain small heaters in each finger whose temperature is controlled by the astronaut and are stuffed with an insulating material.

The boots have the toes of an insulating protection to prevent heat loss. Socks equipped with resistors are also planned.

Because EVA can last almost nine hours, the combination has a system for collecting urine, both solid and liquid, the "Maximum Absorption Garment" (MAG). Older model combination could contain up to 0.95 liters of liquid. The current mix is ​​using a kind of sanitary napkin much more convenient.

Finally, ring connection capable of supporting different levels of pressure are fixed at the ends of different segments (arm, thigh and leg) to unite with other parts tightly with the image of a bayonet. The closures are maintained by the latches locked, mechanical seals and tapes.

The display module and control

On the torso rigid set a display module and control, the "Display and Control Module" (DCM). It allows astronaut to control at any time the status of his suit and connections to external sources of liquids and electricity. It contains all the buttons or levers needed to stop or start the mechanical and electrical systems, adjust the level of pressurization, the valve of the primary purge oxygen and a digital display. This set is powered by a battery of 17 volt silver-zinc which also supplies other elements of the suit and the PLSS.

This module is integrated warning system located in the upper torso, whose role is to ensure that the astronaut knows the status of his suit. If necessary, the combination can be connected to the space shuttle with a cord. It is disconnected before the astronaut leaves the airlock (airlock).

The parts are interchangeable from the combination helmet, rigid upper torso, arms and the assembly of the lower torso.

DCM manufactured by Hamilton Sundstrand. The top is the foreground

As we have said, each pair of arms and legs are manufactured in different sizes which can be adjusted by varying the width of the mounting metal rings that unite the different segments. In this way the lengths of the arms and legs of the combination can be shortened or lengthened by adjusting the width of the rings at the sections of the arms and thighs. This adjustment may be about 2.5 cm to 7.5 cm up arms and leg.

An astronaut takes about 15 minutes to put on his suit. It must first put the LCVG including the cooling system and ventilation. Then he puts on the lower torso (legs and thighs) and then attach his boots. Subsequently, the astronaut fits inside the torso rigid which is already fixed the life support system which, given its weight, is suspended from a hook in the sas special dressing. All systems are then connected and the joints are secured. Astronaut can then put his gloves and helmet. Although in theory the astronaut can equip only in practice and for safety reasons, it actually helped.

The helmet

The helmet (and the means of survival that accompany) worn by the astronauts to protect them from the depressurization, the lack of oxygen and the risk to the vacuum of space. There are basically two models, one focused inside the cabin depressurized, the astronauts wear during maneuvers of the Space Shuttle (including the old model LEH said "clam shell), the other reserved for the EVA.

What we call the "helmet" they carry astronauts during EVA is in fact what NASA calls about the "Helmet Assembly" means a unit composed of two main components: the helmet itself, consisting of a pressurized bubble of glass, anti-shock, anti-fog that was already used by the Apollo crews, and a helmet cover (EVVA) used for protection and support for various accessories and can be seen in the photograph shown at below.

The helmet is manufactured by ILC Dover. It consists of several elements, mainly consisting of a shell more or less oval fiberglass that provides a field of view without any obstruction. The transparency of the visor is secured by the use of polycarbonate, a plastic polymer that replaces the glass as it is more solid and very durable under all variations of this term, including the impact. The visor is very thick, about 3 mm.

The polycarbonate (PC) is marketed under the name Lexan. This material is used to make motorcycle helmets, portholes divers "heavy feet" and the hulls of bike helmets.

The rear of the helmet of the astronauts is covered with an insulating layer of neoprene which is also an anti-shock absorbent and relatively light.

The helmet is equipped with a helmet cover called "Extravehicular Visor Assembly" (EVVA) whose function is to reduce the intensity of solar radiation that strikes the face of the astronaut exposed to direct sunlight. It slides manually and covers the entire surface of the visor. The EVVA also provides additional protection against micro-meteoroids and accidental impacts and protect the astronaut against UV radiation. A special coating made of a multilayer gold is attached to the visor. It is designed to reflect heat (IR) and light, while allowing the astronaut to see through. Adjustable eye protection can also be lowered over the visor to provide additional protection against the glare of the sun and glare.

The different types of helmets used by astronauts:

The helmet with the visor fitted EVVA golden combination A7L used by astronaut Alan Bean during the Skylab 3 mission in 1973.

The helmet worn by the astronaut Roberta Bondar during the STS-42 in 1992. It is not designed for EVA but only for environments with low air or depressurized.

Astronaut Jeffrey Williams with a combination EMU ISS during the STS-101 in 2000

The communication system or "Communications Carrier Assembly" (CCA) consists of several elements. As is done for the pilots, the communicator is a cap woven Teflon fiber (a polymer plastic with very little friction) and Nylon / Lycra (elastic and resistant) worn under the helmet. Nicknamed "Snoopy Cap" (Snoopy's cap), it has two headphones, a microphone and a duplex containing the electrical harness. It attaches with a chin strap. This communication system is attached to the radio placed in the top of the PLSS.

These means allow radio communications between all crew members. Medical information (EEG) also pass with telemetry (data theft techniques) in the CCA and are transmitted in real time on the ground, the Mission Control Center in Houston.

The transceivers used in the EVA have two UHF channels for the transmission of three channels for receiving and a simple switch. These radios have an antenna discrete called "low profile" placed in a box 30x11x9 cm above the PLSS. The set weighs 3.94 kg telecoms which is comparable with portable radios V / UHF trade (taking into account the headset).

A camera is mounted on the helmet cover to save the EVA. Two pairs of headlamps are arranged on both sides of the EVVA to illuminate the object that handles the astronaut example if he is forced to work in the background.

For years before the spacewalk, the astronauts would apply the inner surface of a visor anti-fog spray. That time has passed. Now, to prevent fogging or ice, an electrical lattice son is buried in the polycarbonate to warm. In addition, as we have explained, a small fan is attached to the back and inside of the helmet to deliver oxygen over the head of the astronaut.

In the helmet is also a mouthpiece (a straw) connected to a water bag (IDB), the astronaut can use if he is thirsty. This bag comes in two sizes and is placed in the top of the HUT. It can hold 21 or 32 ounces either 0.6 or 0.9 liters of water. This bag is secured with Velcro.

The transparent inner helmet is placed on a metal ring attachment containing 80 latches that can secure it to the hard upper torso of the suit. Unlike the helmet of Mercury and Gemini suits that turned at the same time as the head of the astronaut from the Apollo missions to the helmet, in theory, could rotate 360 ​​degrees, was fixed when locked to the HUT, which should not increase the feeling of being like a fish in a jar.

Demonstration of the lighting:

Astronaut Carlos Noriega during the STS-97 in 2000

Astronaut Daniel Barry during STS-105 in 2001. It is at a handrail attached to the Destiny laboratory to ISS

The helmet and visor are usually made using the classic technique of molding preformed. Polycarbonate beads are injected into a mold where they are melted and made to form the approximate size of the helmet. When the mold is opened, the main room of the helmet is crafted. It remains to him attach the metal ring mounting, ventilation system, the bleed valve that uses the astronaut with oxygen supply, communication system, the EVVA, headlamps, outdoor camera TMG protection.

Quality control

The manufacturing process of EMU spacesuit is complex. It can be divided into two phases of production. First of all plants confection individual elements. Then they are sent to NASA where they are assembled in factories classics. At this stage of production, the combination is no longer EMU tested in vacuum and can be paid directly by astronaut training for his or her duties.

Quality control is performed at each stage of production process. It ensures that each piece is manufactured in strict compliance with the standards defined in the specifications and operate in the harsh environment of space.

NASA also results of tests completed in the combination of environmental conditions and in vacuum. We check in particular if there is no air leakage, depressurization or malfunction of the system to survive. This quality control is important because the most trivial failure can have dramatic consequences for astronauts exposed to vacuum and the fires of the sun.

The lifetime of a combination of last generation ISS EMU is about 15 years and certified for 25 EVA with routine maintenance between flights. Like the old Apollo suits, it tends to deteriorate and it is estimated that the first models were shattered after about 30 years to 2010. Today we have no solution for this problem and engineers are studying new materials more stable. On the other hand this period is long enough because the combination will in any case outdated technologically and advantageously replaced by more appropriate models, generally lighter, stronger and more compact.

jeudi 5 janvier 2012

NASA's Mars Exploration Rover Opportunity used its navigation camera to capture this view of a northward-facing outcrop, "Greeley Haven," where the rover will work during its fifth Martian winter. Image credit: NASA / JPL-Caltech.

NASA's Mars Exploration Rover Opportunity will spend the next several months at a site informally named "Greeley Haven." The name is a tribute to planetary geologist Ronald Greeley (1939-2011), who was a member of the science team for the Mars rovers and many other interplanetary missions.

The site is an outcrop that provides a sun-facing slope to aid in maintaining adequate solar power during the rover's fifth Martian winter. It also provides targets of scientific interest for the rover's robotic arm to examine.

Closer to the equator than its twin rover, Spirit, Opportunity did not need to stay on a sun-facing slope during previous winters. Now, however, Opportunity's solar panels carry a thicker coating of dust than in the previous winters. Unless an unlikely wind cleans the panels in coming weeks, the team will use a strategy employed for three winters with Spirit: staying on a sun-facing slope. For several months of shortened daylight before and after the southern Mars winter solstice on March 30, 2012, the sun will pass relatively low in the northern sky from the rover's perspective, and Opportunity will work on the north-facing slope.

Plans for research at Greeley Haven include a radio-science investigation of the interior of Mars, which began this week; inspections of mineral compositions and textures on the outcrop; and recording a full-circle, color panorama: the Greeley Panorama. Greeley taught generations of planetary scientists at Arizona State University, Tempe, until his death two months ago.

The radio-science investigation studies tiny wobbles in the rotation of Mars to gain insight about the planet's core. It requires many weeks of radio-tracking the motion of a point on the surface of Mars to measure changes in the spin axis of the planet.

The winter worksite sits on the "Cape York" segment of the rim of Endeavour Crater. Opportunity reached the edge of this 14-mile-wide (22-kilometer-wide) crater five months ago after three years of driving from smaller Victoria Crater, which it studied for two years.

Opportunity and Spirit completed their three-month prime missions in April 2004 and continued for years of bonus, extended missions. Both rovers have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit ended communications in March 2010 as its energy declined after losing the use of two of its six wheels, which prevented it from being able to gain a sun-facing tilt for its fourth Martian winter.

The tranquillityite, a rare mineral found on the moon, was discovered in rocks in Australia.

An ore brought back to Earth by the astronauts who went to the moon and that was long thought to be specific to the Moon, was found in old rocks from Australia more than a billion years, have scientists said Thursday.

Image above: Apollo 11 - Aldrin poses on the Moon, on landing site in the southern Sea of Tranquillity (Mare Tranquillitatis).

The tranquillityite is a mineral that is named after the place where it was found in 1969: Sea of ​​Tranquility, a plain of basalt located on the moon.

This mineral has "long been regarded as a mineral unique to the moon," until geologists find samples in Western Australia, said Birger Rasmussen, an Australian scientist.

Caption: A microscopic image of a rock with red-brown tranquillityite crystals as well as brightly colored pyroxene crystals and grey-white-black feldspar crystals. Credit: Birger Rasmussen.

"He had never been found in other terrestrial samples" for over 40 years, told AFP the scientific, Curtin University, Perth (west).

"They did not come from the Moon"

Samples of the moon were considered "extremely valuable" and were subjected to very detailed amount of exams, when we were in fact "has always been under our noses," he noted.

"We have always been on Earth, they are not just coming from the moon," said the scientist, who published his research in the publication Geology. "This means that basically we have the same chemical phenomena and the same processes that occur on the Moon and on Earth."

The Moon

This mineral, rare, has so far been found in six different locations in Australia. Particular, it allows a precise dating of rocks that contain it, said Birger Rasmussen.

Which brings us back to the question: How these are formed the earth and the moon? There are three main theories:

Theory of fission

During the early youth of the Earth, it is still hot and soft, our planet would have turned fast enough on itself to flatten the globe and brings out by centrifugal force, part of its material . The ejected material would then remained trapped in the terrestrial gravitational field, and would have formed the Moon Lunar after cooling. This theory is contradicted by the nature of the chemical composition between the two stars, which is remarkably different, especially in the proportion of iron.

Theory of the simultaneous formation

During contraction of the gaseous material of proto planetary disk, the Moon and Earth were formed simultaneously and jointly from the same "lump" on earth. Always fanciful idea in terms of the difference in chemical composition of rocks ... Moreover, this theory is not able to account for the difference in size between the core proportional lunar and Earth's core.

Theory of collision

Fortunately, planetary scientists proposed in recent years athird scenario that seems to fit all the criteria: that of the collision.

How the Moon was born

This theory postulates that, very early in the history of the solar system, when Earth was still a malleable ball of molten rock, a planetoid the size of Mars collided with it. This hypothetical planet even has a name: Theia.

The violence of the shock would have removed a huge amount of matter in space, a significant part would have remained trapped in the gravitational field, the other beyond ever the power of attraction.
This material is entered into orbit rotation (according to the rotary motion of the Earth) and would be flattened disc-shaped, to form a ring of dust and rocks similar to those of Saturn's ring ... But this land would agglomerated in the space of just a few years, forming a spherical mass and warm, which on cooling became our Moon.

As for the planetoid responsible for the collision, it is thought that its nucleus would have largely been absorbed by the Earth's core and mantle, the rest going to form the core of the Moon.

This theory, supported by the analysis of samples of lunar rocks brought back during the Apollo missions, has also passed various simulations to estimate the age of the collision 42 million years after solar system formation.

The Moon is much lighter than the Earth, and indeed, the simulations show that it is the light elements of our planet that would have mostly been ejected into space and that would have been likely to form the Moon. The fact is that the Moon has the same minerals as the Earth, but in different proportions: The light elements are very present, very little heavy ...

In addition, at the time of the collision, the iron core of the Earth was already almost formed, which explains the very small proportion of iron in the Moon compared to that of Earth.

To date, all the differences and similarities between the composition of our planet and the Moon can be explained by that theory, so it's more accepted today. It explains how one side their elements have a common origin, while providing the reason for the difference in proportions between the two ... Finally, it explains why our planet is the only planet in the inner solar system to have a satellite if bulk.

mercredi 4 janvier 2012

A new image of the Omega Nebula, captured by ESO's Very Large Telescope (VLT), is one of the sharpest of this object ever taken from the ground. It shows the dusty, rose-coloured central parts of this famous stellar nursery and reveals extraordinary detail in the cosmic landscape of gas clouds, dust and newborn stars.

The colourful gas and dark dust in the Omega Nebula serve as the raw materials for creating the next generation of stars. In this particular section of the nebula, the newest stars on the scene — dazzlingly bright and shining blue-white — light up the whole ensemble. The nebula's smoky-looking ribbons of dust stand in silhouette against the glowing gas. The dominant reddish colours of this portion of the cloud-like expanse, arise from hydrogen gas, glowing under the influence of the intense ultraviolet rays from the hot young stars.

The Omega Nebula goes by many names, depending on who observed it when and what they thought they saw. These other titles include the Swan Nebula, the Horseshoe Nebula and even the Lobster Nebula. The object has also been catalogued as Messier 17 (M17) and NGC 6618. The nebula is located about 6500 light-years away in the constellation of Sagittarius (The Archer). A popular target of astronomers, this illuminated gas and dust field ranks as one of the youngest and most active stellar nurseries for massive stars in the Milky Way.

Zooming in on the Omega Nebula

The image was taken with the FORS (FOcal Reducer and Spectrograph) instrument on Antu, one of the four Unit Telescopes of the VLT. In addition to the huge telescope, exceptionally steady air during the observations, despite some clouds, also helped make the crispness of this image possible [1]. As a result this new picture is among the sharpest of this part of the Omega Nebula ever taken from the ground.

This image is one of the first to have been produced as part of the ESO Cosmic Gems programme [2].

Notes:

[1] The "seeing" — a term astronomers use to measure the distorting effects of Earth's atmosphere — on the night of the observations was very good. A common measure for seeing is the apparent diameter of a star when seen through a telescope. In this case, the measure of seeing was an extremely favourable 0.45 arcseconds meaning little blurring and twinkling of the object of interest.

[2] The ESO Cosmic Gems programme is an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of small amounts of observing time, combined with otherwise unused time on the telescopes’ schedules so as to minimise the impact on science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

More information:

The year 2012 marks the 50th anniversary of the founding of the European Southern Observatory (ESO). ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

mardi 3 janvier 2012

Hubble's panchromatic vision, stretching from ultraviolet through near-infrared wavelengths, reveals the vibrant glow of young, blue star clusters and a glimpse into regions normally obscured by the dust.

The warped shape of Centaurus A's disk of gas and dust is evidence for a past collision and merger with another galaxy. The resulting shockwaves cause hydrogen gas clouds to compress, triggering a firestorm of new star formation. These are visible in the red patches in this Hubble close-up.

At a distance of just over 11 million light-years, Centaurus A contains the closest active galactic nucleus to Earth. The center is home for a supermassive black hole that ejects jets of high-speed gas into space, but neither the supermassive black hole or the jets are visible in this image.

lundi 2 janvier 2012

The second of NASA's two Gravity Recovery And Interior Laboratory (GRAIL) spacecraft has successfully completed its planned main engine burn and is now in lunar orbit. Working together, GRAIL-A and GRAIL-B will study the moon as never before.

"NASA greets the new year with a new mission of exploration," said NASA Administrator Charles Bolden. "The twin GRAIL spacecraft will vastly expand our knowledge of our moon and the evolution of our own planet. We begin this year reminding people around the world that NASA does big, bold things in order to reach for new heights and reveal the unknown."

GRAIL-B achieved lunar orbit at 2:43 p.m. PST (5:43 p.m. EST) today. GRAIL-A successfully completed its burn yesterday at 2 p.m. PST (5 p.m. EST). The insertion maneuvers placed the spacecraft into a near-polar, elliptical orbit with an orbital period of approximately 11.5 hours. Over the coming weeks, the GRAIL team will execute a series of burns with each spacecraft to reduce their orbital period to just under two hours. At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers).

Artist concept of GRAIL mission. Grail will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail.

During GRAIL's science mission, the two spacecraft will transmit radio signals precisely defining the distance between them. As they fly over areas of greater and lesser gravity caused by visible features such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.

Scientists will translate this information into a high-resolution map of the moon's gravitational field. The data will allow scientists to understand what goes on below the lunar surface. This information will increase knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.

Twin Spacecraft Bound for the Moon

Each spacecraft carries a small camera called GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students) with the sole purpose of education and public outreach. The MoonKAM program is led by Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego.

GRAIL MoonKAM will engage middle schools across the country in the GRAIL mission and lunar exploration. Thousands of fifth- to eighth-grade students will select target areas on the lunar surface and send requests to the GRAIL MoonKAM Mission Operations Center in San Diego. Photos of the target areas will be sent back by the GRAIL satellites for students to study.

A student contest that began in October 2011 also will choose new names for the spacecraft. The new names are scheduled to be announced in January 2012. Ride and Maria Zuber, the mission's principal investigator at the Massachusetts Institute of Technology in Cambridge, chaired the final round of judging.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the GRAIL mission for NASA's Science Mission Directorate, Washington. The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver built the spacecraft.

dimanche 1 janvier 2012

The first of two NASA spacecraft to study the moon in unprecedented detail has entered lunar orbit.

NASA's Gravity Recovery And Interior Laboratory (GRAIL)-A spacecraft successfully completed its planned main engine burn at 2 p.m. PST (5 p.m. EST) today. As of 3 p.m. PST (6 p.m. EST), GRAIL-A is in an orbit of 56 miles by 5,197 miles (90 kilometers by 8,363 kilometers) around the moon that takes approximately 11.5 hours to complete.

"My resolution for the new year is to unlock lunar mysteries and understand how the moon, Earth and other rocky planets evolved," said Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology in Cambridge. "Now, with GRAIL-A successfully placed in orbit around the moon, we are one step closer to achieving that goal."

The next mission milestone occurs tomorrow when GRAIL-A's mirror twin, GRAIL-B, performs its own main engine burn to place it in lunar orbit. At 3 p.m. PST (6 p.m. EST) today, GRAIL-B was 30,018 miles (48,309 kilometers) from the moon and closing at a rate of 896 mph (1,442 kilometers per hour). GRAIL-B's insertion burn is scheduled to begin tomorrow, Jan. 1, at 2:05 p.m. PST (5:05 p.m. EST) and will last about 39 minutes.

"With GRAIL-A in lunar orbit we are halfway home," said David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Tomorrow may be New Year's everywhere else, but it's another work day around the moon and here at JPL for the GRAIL team."

GRAIL-A Spacecraft Arrives at the Moon

Once both spacecraft are confirmed in orbit and operating, science work will begin in March. The spacecraft will transmit radio signals precisely defining the distance between them as they orbit the moon in formation. As they fly over areas of greater and lesser gravity caused by both visible features, such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.

Scientists will translate this information into a high-resolution map of the moon's gravitational field. The data will allow scientists to understand what goes on below the lunar surface. This information will increase knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.

JPL manages the GRAIL mission for NASA's Science Mission Directorate at the agency's headquarters in Washington. The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver built the spacecraft.